Liquid containers featuring drain-back spout fitments and closures that double as measuring/dosing cups are very well known in the packaging industry and are widely used for many consumer liquid detergent products, especially liquid laundry detergents and fabric softeners. The basic premise behind this universally recognized package is the merger of three plastic parts, namely a bottle with an opening, a drain-back pour spout fitment fitted into the opening, and a threaded measuring cup that can be inverted and screwed over the drain-back spout to close the container. The packaging industry has improved these packaging components over the years for cost, better functionality, ease of assembly on filled containers, and ease of use for the consumer. However, in spite of continual modifications to this type of liquid packaging, problems with the packaging still remain and a need for continued improvement exists. The changes over the years focused on improvements to dripping, double pouring, slow drain-back, and poor sealing between the bottle and the fitment and between the fitment and the closure. None of these modifications improve (1) the sealing between the closure and the fitment when only minimal torque is applied by a consumer who replaces the closure, (2) maintenance of that torque applied to the closure such that the seal between the closure and fitment can be held between consumer uses, and (3) locking of the fitment onto the bottle in the correct orientation with respect to the way the consumer will hold and lift the bottle (e.g., foolproof orientation of the pour spout such that it aims to the direction the bottle is designed to pour).
The basic liquid package with drain back feature may be found in U.S. Pat. No. 4,550,862 issued to The Procter & Gamble Company in 1985 (Barker). Since then, various improvements to this basic concept can be seen throughout the past two decades or so.
U.S. Pat. No. 4,696,416 (issued to Muckenfuhs) incorporated a “drip concentrator” at the drain back hole such that residual liquid would coalesce and drip back into the bottle. This reduced some of the messiness of these systems by collecting and draining back residual liquid more efficiently.
U.S. Pat. No. 4,917,268 (issued to Campbell) claimed improvements to the centering and fit of the pouring spout fitment into the bottle opening through use of a plurality of teeth inter-engaging with cooperating ramp projections.
U.S. Pat. No. 5,058,772 (issued to Moore) claimed improvements to the sealing between the spout fitment and the bottle opening lip by incorporating a “V”-shaped slot up underneath the fitment skirt that engages with the lip of the bottle opening. Moore has also described leveling formations on the bottom of the fitment to facilitate automated assembly.
U.S. Pat. No. 5,251,788 (also issued to Moore) claims improved pouring and drain back through an offset spout with a uniquely contoured pouring lip.
U.S. Pat. No. 5,431,306 (issued to Reid) focusing on the seal between the fitment and the neck of the bottle. The design of the fitment and the neck allow for ultrasonic welding between these two melt-flow compatible surfaces.
U.S. Pat. Nos. 5,462,202 and 5,566,862, (issued to Haffner), claim modification to the basic drain back packaging system. The cap features a collar with internal threads that are designed to close completely over the neck of the bottle. However, the fitment has limited sealing surfaces to the opening of the container since there are no threads. Leakage is possible around the cap threads and out to the outer circumference of the neck and this system is prone to the spout fitment falling back inside the bottle.
U.S. Pat. No. 5,603,787 (issued to Reid) claims a better seal between the spout fitment and the neck of the bottle using an ultrasonic weld between the surfaces.
U.S. Pat. Nos. 6,032,829 and 6,223,946, (issued to Geisinger), claim an improved seal through the deformation of a v-shaped rib on the neck of the bottle with a circumferential flange around the skirt of the cap. In this invention, the cap seals against the top edge of the neck of the bottle rather than onto the spout fitment. The spout is molded as an integral part of the bottle and not attached as a separate fitment.
U.S. Pat. No. 6,279,789 (Krall), U.S. Pat. No. 6,398,076 (Giblin), U.S. Pat. No. 6,659,310 (Wolpert) and U.S. Pat. No. 6,923,341 (Smith) claim further improvements to the basic drain back spout package, incorporating various designs for sealing of the cap to either the neck of the bottle or to the spout fitment, (one of which includes spin-welding), improving the pouring and the drain back efficiency, or making the closure child-resistant.